2025/03/31 更新

写真a

イトウ ダイユウ
伊藤 大裕
Daiyu Ito
所属
大学院 総合研究部 生命環境学域 生命農学系(生命工学) 助教
職名
助教
外部リンク

論文上での記載著者名

  • Daiyu Ito

研究分野

  • ライフサイエンス / 発生生物学  / 生命工学、発生工学、宇宙生殖工学

研究キーワード

  • 生命工学、発生工学、宇宙生殖工学

共同研究・競争的資金等の研究

  • 動物遺伝資源の室温永久保存を可能にする新技術の開発

    研究課題/領域番号:24K01779  2024年4月 - 2026年3月

    科学研究費助成事業   基盤研究(B)

      詳細を見る

    担当区分:研究分担者  資金種別:競争的資金  資金の種類:科学研究費補助金

  • フリーズドライ精子の低出産率改善に向けた精子選別及び卵子の前処理に関する研究

    研究課題/領域番号:23K19330  2023年8月 - 2025年3月

    日本学術振興会  山梨大学  科学研究費助成事業  研究活動スタート支援

    伊藤 大裕

      詳細を見る

    資金種別:競争的資金  資金の種類:科学研究費補助金

  • フリーズドライ精子の室温保存を実用化するための新規技術開発

    研究課題/領域番号:20J23364  2020年4月 - 2023年3月

    日本学術振興会  山梨大学  科学研究費助成事業  特別研究員奨励費

    伊藤 大裕

      詳細を見る

    哺乳類精子は、遺伝資源の保存を目的として多様な動物種を対象に世界中で保存され、液体窒素タンクでの保存が広く普及している。味噌汁をはじめ食品は、冷凍保存だけでなく、フリーズドライ(凍結乾燥)処理すると室温保存できる。フリーズドライ精子は1998年に初成功が報告されて以来、保存にはガラスアンプル瓶が使われてきたが、割れると精子を保存できなくなるリスクがあった。そのため、前年度は精子を薄いプラスチックシートに挟んで保存する技術を開発し、さらにハガキに貼り付けてポストから簡便に国内郵送するところまで成功した。だがフリーズドライ精子は、アンプル瓶で保存した場合1年以上室温保存できたのに対し、シートの場合は冷凍であれば少なくとも3ヶ月間は保存できたが、室温では3日間までしか保存できなかった。そこで最終年度は、室温でもフリーズドライ精子を長期保存できるシート保存技術の開発に重点を置いた。数種類のシートで1週間保存したが、室温保存の結果(顕微授精後の受精率及び発生率)は、-30℃と比較して著しく低下した。最終的に脱酸素剤と乾燥剤を精子と一緒に保存する方法を開発し、3ヶ月間の室温保存を試した全4系統のマウス精子すべてで仔マウスを作出することに成功した。本成果の一部は、日本繁殖生物学会大会やCryopreservation Conferenceで発表した。年度内に論文を発表できなかったが、追加実験をまとめ、国際誌に論文を発表する予定である。本技術が実用レベルに至れば、室温管理が可能な精子のアルバム保存や精子の国際郵送など、利便性の高い技術として社会に貢献できると考え、改良には最適な凍結乾燥保護剤について検討を進める必要がある。同時に、本研究の実用化には、遺伝資源の不正輸出など悪用を未然に防ぐための備えが不可欠であり、国際的な法整備をはじめ対策を十分に検討する必要がある。

論文

  • Extracting and analyzing micronuclei from mouse two-cell embryos fertilized with freeze-dried spermatozoa. 査読

    Ikue Shibasaki, Hinata Sugiyama, Yuko Kamada, Hiroaki Nagatomo, Daiyu Ito, Sayaka Wakayama, Masatoshi Ooga, Tsuyoshi Kasai, Takashi Kohda, Teruhiko Wakayama

    Communications biology   8 ( 1 )   6 - 6   2025年1月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Abnormal chromosome segregation (ACS) in preimplantation embryos causes miscarriages. For a normal pregnancy, it is necessary to reduce ACS occurrences in embryos. However, the causes of such abnormalities are unclear because no method to extract the segregated chromosomes from the blastomeres for detailed analysis. This study attempted to extract micronuclei derived from segregated chromosomes of mouse embryos. Some micronuclei in blastomeres were bound to the nucleus by DNA cross-links, some were bound to tubulin, and about half of the micronuclei had major satellite regions. By depolymerizing the cytoskeleton of blastomeres with cytochalasin B and colcemid, some micronuclei could be extracted from blastomeres of ACS embryos using a glass needle of a micromanipulator. DNA-sequencing results of each extracted micronucleus revealed that chromosomes in micronuclei were randomly selected, usually only one, and often contained a portion rather than the full length of the chromosome. This study allows a detailed analysis of micronuclei and facilitates the mechanism of the causes of ACS in embryos.

    DOI: 10.1038/s42003-024-07358-0

    PubMed

  • Method for long-term room temperature storage of mouse freeze-dried sperm 査読

    Scientific Reports   15 ( 1 )   2025年1月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1038/s41598-024-83350-2

  • Kdm4d mutant mice show impaired sperm motility and subfertility 査読

    70 ( 5 )   320 - 326   2024年10月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1262/jrd.2024-039

  • Time-lapse observation of mouse preimplantation embryos using a simple closed glass capillary method. 査読

    Yasuyuki Kikuchi, Daiyu Ito, Sayaka Wakayama, Masatoshi Ooga, Teruhiko Wakayama

    Scientific reports   13 ( 1 )   19893 - 19893   2023年11月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Time-lapse observation is a popular method for analyzing mammalian preimplantation embryos, but it often requires expensive equipment and skilled techniques. We previously developed a simply and costly embryo-culture system in a sealed tube that does not require a CO2 incubator. In the present study, we developed a new time-lapse observation system using our previous culture method and a glass capillary. Zygotes were placed in a glass capillary and sunk in oil for observation under a stereomicroscope. Warming the capillary using a thermoplate enabled most of the zygotes to develop into blastocysts and produce healthy offspring. This time-lapse observation system captured images every 30 min for up to 5 days, which confirmed that the developmental speed and quality of the embryos were not affected, even with fluorescence. Overall, this new system is a simple time-lapse observation method for preimplantation embryos that does not require dedicated machines and advanced techniques.

    DOI: 10.1038/s41598-023-47017-8

    PubMed

  • Aberrant histone methylation in mouse early preimplantation embryos derived from round spermatid injection. 査読

    Masatoshi Ooga, Yasuyuki Kikuchi, Daiyu Ito, Kousuke Kazama, Rei Inoue, Mizuki Sakamoto, Sayaka Wakayama, Teruhiko Wakayama

    Biochemical and biophysical research communications   680   119 - 126   2023年11月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Round spermatid injection (ROSI) is the last resort and recourse for men with nonobstructive azoospermia to become biological fathers of their children. However, the ROSI-derived offspring rate is lower than intracytoplasmic sperm injection (ICSI) in mice (20% vs. 60%). This low success rate has hindered the spread of ROSI in ART (Assisted Reproductive Technology). However, the cause of the ROSI-zygote-derived low offspring rate is currently unknown. In the previous studies, we reported that H3K9me3 and H3K27me3 exhibited ectopic localizations in male pronuclei (mPN) of ROSI-zygotes, suggesting that the carried over histone to zygotes conveys epigenetic information. In this study, we analyzed other histone modifications to explore unknown abnormalities. H3K36me3 showed an increased methylation state compared to ICSI-derived embryos but not for H3K4me3. Abnormal H3K36me3 was corrected until 2-cell stage embryos, suggesting a long window of reprogramming ability in ROSI-embryos. Treatment with TSA of ROSI-zygotes, which was reported to be capable of correcting ectopic DNA methylation in ROSI-zygotes, caused abnormalities of H3K36me3 in male and female PN (fPN) of the zygotes. In contrast, round spermatid TSA treatment before ROSI, which was reported to improve the preimplantation development of ROSI-zygotes, showed beneficial effects without toxicity in fPN. Therefore, the results suggest that TSA has some negative effects, but overall, it is effective in the correction of epigenetic abnormalities in ROSI-zygotes. When attempting to correct epigenetic abnormalities, attention should be paid to epigenomes not only in male but also in female pronuclei.

    DOI: 10.1016/j.bbrc.2023.09.020

    PubMed

  • A novel, simplified method to prepare and preserve freeze-dried mouse sperm in plastic microtubes. 査読

    Li Ly Yang, Daiyu Ito, Natsuki Ushigome, Sayaka Wakayama, Masatoshi Ooga, Teruhiko Wakayama

    The Journal of reproduction and development   69 ( 4 )   198 - 205   2023年8月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Although freeze-drying sperm can save space, reduce maintenance costs, and facilitate the transportation of genetic samples, the current method requires breakable, custom-made, and expensive glass ampoules. In the present study, we developed a simple and economical method for collecting freeze-dried (FD) sperm using commercially available plastic microtubes. Mouse epididymal sperm suspensions were placed in 1.5 ml polypropylene tubes, frozen in liquid nitrogen, and dried in an acrylic freeze-drying chamber, after which they were closed under a vacuum. The drying duration did not differ between the microtube and glass ampoule methods (control); however, the sperm recovery rate was higher using the microtube method, and the physical damage to the sperm after rehydration was also reduced. Intracytoplasmic sperm injection (ICSI) using FD sperm stored in microtubes at -30°C yielded healthy offspring without reducing the success rate, even after 9 months of storage. Air infiltration into all microtubes stored at room temperature (RT) within 2 weeks of storage caused a drastic decrease in the fertilization rate of FD sperm; underwater storage did not prevent air infiltration. RT storage of FD sperm in microtubes for 1 week resulted in healthy offspring after ICSI (5-18%), but the addition of silica gel or CaCl2 did not improve the success rate. Our novel microtube method is currently the simplest and most effective method for treating FD sperm, contributing to the development of alternative low-cost approaches for preserving and transporting genetic resources.

    DOI: 10.1262/jrd.2023-034

    PubMed

  • Production of mouse offspring from zygotes fertilized with freeze-dried spermatids. 査読

    Sayaka Wakayama, Daiyu Ito, Masatoshi Ooga, Teruhiko Wakayama

    Scientific reports   12 ( 1 )   18430 - 18430   2022年11月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Mouse cloning by nuclear transfer using freeze-drying (FD) somatic cells is now possible, but the success rate is significantly lower than that of FD spermatozoa. Because spermatozoa, unlike somatic cells, are haploid cells with hardened nuclei due to protamine, the factors responsible for their tolerance to FD treatment remain unclear. In this study, we attempt to produce offspring from FD spermatid, a haploid sperm progenitor cell whose nuclei, like somatic cells, have not yet been replaced by protamine. We developed a method for collecting FD spermatids from testicular suspension. Despite the significantly lower success rate than that of FD spermatozoa, healthy offspring were obtained when FD spermatids were injected into oocytes. Offspring were also obtained from FD spermatids derived from immature male mice that had not yet produced spermatozoa. These results suggest that nuclear protaminization, rather than haploid nuclei, is one of the key processes responsible for tolerance to FD treatment.

    DOI: 10.1038/s41598-022-22850-5

    PubMed

  • Paternally inherited H3K27me3 affects chromatin accessibility in mouse embryos produced by round spermatid injection. 査読

    Mizuki Sakamoto, Daiyu Ito, Rei Inoue, Sayaka Wakayama, Yasuyuki Kikuchi, Li Yang, Erika Hayashi, Rina Emura, Hirosuke Shiura, Takashi Kohda, Satoshi H Namekawa, Takashi Ishiuchi, Teruhiko Wakayama, Masatoshi Ooga

    Development (Cambridge, England)   149 ( 18 )   2022年9月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Round spermatid injection (ROSI) results in a lower birth rate than intracytoplasmic sperm injection, which has hampered its clinical application. Inefficient development of ROSI embryos has been attributed to epigenetic abnormalities. However, the chromatin-based mechanism that underpins the low birth rate in ROSI remains to be determined. Here, we show that a repressive histone mark, H3K27me3, persists from mouse round spermatids into zygotes in ROSI and that round spermatid-derived H3K27me3 is associated with less accessible chromatin and impaired gene expression in ROSI embryos. These loci are initially marked by H3K27me3 but undergo histone modification remodelling in spermiogenesis, resulting in reduced H3K27me3 in normal spermatozoa. Therefore, the absence of epigenetic remodelling, presumably mediated by histone turnover during spermiogenesis, leads to dysregulation of chromatin accessibility and transcription in ROSI embryos. Thus, our results unveil a molecular logic, in which chromatin states in round spermatids impinge on chromatin accessibility and transcription in ROSI embryos, highlighting the importance of epigenetic remodelling during spermiogenesis in successful reproduction.

    DOI: 10.1242/dev.200696

    PubMed

  • Production of offspring from vacuum-dried mouse spermatozoa and assessing the effect of drying conditions on sperm DNA and embryo development. 査読

    Natsuki Ushigome, Sayaka Wakayama, Kango Yamaji, Daiyu Ito, Masatoshi Ooga, Teruhiko Wakayama

    The Journal of reproduction and development   68 ( 4 )   262 - 270   2022年8月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Freeze-dried sperm (FD sperm) are of great value because they can be stored at room temperature for long periods of time, However, the birth rate of offspring derived from FD sperm is low and the step in the freeze-drying process particularly responsible for low offspring production remains unknown. In this study, we determined whether the drying process was responsible for the low success rate of offspring by producing vacuum-dried sperm (VD sperm), using mouse spermatozoa dried in a vacuum without being frozen. Transfer of embryos fertilized with VD sperm to recipients resulted in the production of several successful offspring. However, the success rate was slightly lower than that of FD sperm. The volume, temperature, and viscosity of the medium were optimized to improve the birth rate. The results obtained from a comet assay indicated that decreasing the drying rate reduced the extent of DNA damage in VD sperm. Furthermore, even though the rate of blastocyst formation increased upon fertilization with VD sperm, full-term development was not improved. Analysis of chromosomal damage at the two-cell stage through an abnormal chromosome segregation (ACS) assay revealed that reduction in the drying rate failed to prevent chromosomal damage. These results indicate that the lower birth rate of offspring from FD sperm may result from the drying process rather than the freezing process.

    DOI: 10.1262/jrd.2022-048

    PubMed

  • Healthy cloned offspring derived from freeze-dried somatic cells. 査読

    Sayaka Wakayama, Daiyu Ito, Erika Hayashi, Takashi Ishiuchi, Teruhiko Wakayama

    Nature communications   13 ( 1 )   3666 - 3666   2022年7月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Maintaining biodiversity is an essential task, but storing germ cells as genetic resources using liquid nitrogen is difficult, expensive, and easily disrupted during disasters. Our aim is to generate cloned mice from freeze-dried somatic cell nuclei, preserved at -30 °C for up to 9 months after freeze drying treatment. All somatic cells died after freeze drying, and nucleic DNA damage significantly increased. However, after nuclear transfer, we produced cloned blastocysts from freeze-dried somatic cells, and established nuclear transfer embryonic stem cell lines. Using these cells as nuclear donors for re-cloning, we obtained healthy cloned female and male mice with a success rate of 0.2-5.4%. Here, we show that freeze-dried somatic cells can produce healthy, fertile clones, suggesting that this technique may be important for the establishment of alternative, cheaper, and safer liquid nitrogen-free bio-banking solutions.

    DOI: 10.1038/s41467-022-31216-4

    PubMed

  • Mouse in vivo-derived late 2-cell embryos have higher developmental competence after high osmolality vitrification and -80°C preservation than IVF or ICSI embryos. 査読

    Erika Hayashi, Sayaka Wakayama, Daiyu Ito, Ayumi Hasegawa, Keiji Mochida, Masatoshi Ooga, Atsuo Ogura, Teruhiko Wakayama

    The Journal of reproduction and development   68 ( 2 )   118 - 124   2022年4月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Mammalian embryos are most commonly cryopreserved in liquid nitrogen; however, liquid nitrogen is not available in special environments, such as the International Space Station (ISS), and vitrified embryos must be stored at -80°C. Recently, the high osmolarity vitrification (HOV) method was developed to cryopreserve mouse 2-cell stage embryos at -80°C; however, the appropriate embryo is currently unknown. In this study, we compared the vitrification resistance of in vivo-derived, in vitro fertilization (IVF)-derived, and intracytoplasmic sperm injection (ICSI)-derived mouse 2-cell embryos against cryopreservation at -80°C. The ICSI embryos had lower survival rates after warming and significantly lower developmental rates than the in vivo and IVF embryos. Further, IVF embryos had a lower survival rate after warming, but a similar rate to the in vivo embryos to full-term development. This result was confirmed by simultaneous vitrification of in vivo and IVF embryos in the same cryotube using identifiable green fluorescent protein-expressing embryos. We also evaluated the collection timing of the in vivo embryos from the oviduct and found that late 2-cell embryos had higher survival and developmental rates to full-term than early 2-cell embryos. Some early 2-cell embryos remained in the S-phase, whereas most late 2-cell embryos were in the G2-phase, which may have affected the tolerance to embryo vitrification. In conclusion, when embryos must be cryopreserved under restricted conditions, such as the ISS, in vivo fertilized embryos collected at the late 2-cell stage without long culture should be employed.

    DOI: 10.1262/jrd.2021-115

    PubMed

  • Protocol to preserve mouse freeze-dried spermatozoa in the thin plastic sheets. 査読

    Daiyu Ito, Teruhiko Wakayama

    STAR protocols   2 ( 4 )   100933 - 100933   2021年12月

     詳細を見る

    担当区分:筆頭著者, 責任著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The preservation of mammalian freeze-dried (FD) spermatozoa is commonly performed using small glass ampules; however, they are bulky and breakable. In this study, we present a protocol to prepare and preserve mouse FD sperm using thin plastic sheets. This approach allows storing thousands of mouse strains in a card folder. We can also send the FD sperm domestically using a postcard without any extra equipment. For complete details on the use and execution of this protocol, please refer to Ito et al. (2021).

    DOI: 10.1016/j.xpro.2021.100933

    PubMed

  • Mailing viable mouse freeze-dried spermatozoa on postcards. 査読

    Daiyu Ito, Sayaka Wakayama, Rina Emura, Masatoshi Ooga, Teruhiko Wakayama

    iScience   24 ( 8 )   102815 - 102815   2021年8月

     詳細を見る

    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Freeze-drying techniques allow the preservation of mammalian spermatozoa without using liquid nitrogen. However, the current method requires the use of glass ampoules, which are breakable, expensive, and bulky to store or transport. In this study, we evaluated whether mouse freeze-dried (FD) spermatozoa can be preserved and transported on thin materials. In this study, we demonstrated that FD sperm can be preserved in thin plastic sheets. Its DNA integrity was comparable to that of glass ampoule spermatozoa, and healthy offspring were obtained after preservation at -30°C for more than 3 months. We attached preserved FD sperm to postcards, and transported these to other laboratory inexpensively at room temperatures without any protection. This method will facilitate the preservation of thousands of mouse strains in a single card holder, promote collaboration between laboratories, conservation of genetic resources, and assisted reproductive technology.

    DOI: 10.1016/j.isci.2021.102815

    PubMed

  • Evaluating the long-term effect of space radiation on the reproductive normality of mammalian sperm preserved on the International Space Station. 査読

    Sayaka Wakayama, Daiyu Ito, Yuko Kamada, Toru Shimazu, Tomomi Suzuki, Aiko Nagamatsu, Ryoko Araki, Takahiro Ishikawa, Satoshi Kamimura, Naoki Hirose, Kousuke Kazama, Li Yang, Rei Inoue, Yasuyuki Kikuchi, Erika Hayashi, Rina Emura, Ren Watanabe, Hiroaki Nagatomo, Hiromi Suzuki, Tohru Yamamori, Motoki N Tada, Ikuko Osada, Masumi Umehara, Hiromi Sano, Haruo Kasahara, Akira Higashibata, Sachiko Yano, Masumi Abe, Satoshi Kishigami, Takashi Kohda, Masatoshi Ooga, Teruhiko Wakayama

    Science advances   7 ( 24 )   2021年6月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Space radiation may cause DNA damage to cells and concern for the inheritance of mutations in offspring after deep space exploration. However, there is no way to study the long-term effects of space radiation using biological materials. Here, we developed a method to evaluate the biological effect of space radiation and examined the reproductive potential of mouse freeze-dried spermatozoa stored on the International Space Station (ISS) for the longest period in biological research. The space radiation did not affect sperm DNA or fertility after preservation on ISS, and many genetically normal offspring were obtained without reducing the success rate compared to the ground-preserved control. The results of ground x-ray experiments showed that sperm can be stored for more than 200 years in space. These results suggest that the effect of deep space radiation on mammalian reproduction can be evaluated using spermatozoa, even without being monitored by astronauts in Gateway.

    DOI: 10.1126/sciadv.abg5554

    PubMed

  • Optimised CO2-containing medium for in vitro culture and transportation of mouse preimplantation embryos without CO2 incubator. 査読

    Yasuyuki Kikuchi, Sayaka Wakayama, Daiyu Ito, Masatoshi Ooga, Teruhiko Wakayama

    PloS one   16 ( 12 )   e0260645   2021年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Conventional in vitro culture and manipulation of mouse embryos require a CO2 incubator, which not only increases the cost of performing experiments but also hampers the transport of embryos to the other laboratories. In this study, we established and tested a new CO2 incubator-free embryo culture system and transported embryos using this system. Using an Anaero pouch, which is a CO2 gas-generating agent, to increase the CO2 partial pressure of CZB medium to 4%-5%, 2-cell embryos were cultured to the blastocyst stage in a sealed tube without a CO2 incubator at 37°C. Further, the developmental rate to blastocyst and full-term development after embryo transfer were comparable with those of usual culture method using a CO2 incubator (blastocyst rate: 97% versus 95%, respectively; offspring rate: 30% versus 35%, respectively). Furthermore, using a thermal bottle, embryos were reliably cultured using this system for up to 2 days at room temperature, and live offspring were obtained from embryos transported in this simple and very low-cost manner without reducing the offspring rate (thermal bottle: 26.2% versus CO2 incubator: 34.3%). This study demonstrates that CO2 incubators are not essential for embryo culture and transportation and that this system provides a useful, low-cost alternative for mouse embryo culture and manipulation.

    DOI: 10.1371/journal.pone.0260645

    PubMed

  • Removal of remodeling/reprogramming factors from oocytes and the impact on the full-term development of cloned embryos. 査読

    Shunsuke Konno, Sayaka Wakayama, Daiyu Ito, Kousuke Kazama, Naoki Hirose, Masatoshi Ooga, Teruhiko Wakayama

    Development (Cambridge, England)   147 ( 15 )   2020年8月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The reason for the poor development of cloned embryos is not yet clear. Several reports have suggested that some nuclear remodeling/reprogramming factors (RRFs) are removed from oocytes at the time of enucleation, which might cause the low success rate of animal cloning. However, there is currently no method to manipulate the amount of RRFs in oocytes. Here, we describe techniques we have developed to gradually reduce RRFs in mouse oocytes by injecting somatic cell nuclei into oocytes. These injected nuclei were remodeled and reprogrammed using RRFs, and then RRFs were removed by subsequent deletion of somatic nuclei from oocytes. The size of the metaphase II spindle reduced immediately, but did recover when transferred into fresh oocytes. Though affected, the full-term developmental potential of these RRF-reduced oocytes with MII-spindle shrinkage was not lost after fertilization. When somatic cell nuclear transfer was performed, the successful generation of cloned mice was somewhat improved and abnormalities were reduced when oocytes with slightly reduced RRF levels were used. These results suggest that a change in RRFs in oocytes, as achieved by the method described in this paper or by enucleation, is important but not the main reason for the incomplete reprogramming of somatic cell nuclei.

    DOI: 10.1242/dev.190777

    PubMed

  • Effect of trehalose on the preservation of freeze-dried mice spermatozoa at room temperature. 査読

    Daiyu Ito, Sayaka Wakayama, Yuko Kamada, Ikue Shibasaki, Satoshi Kamimura, Masatoshi Ooga, Teruhiko Wakayama

    The Journal of reproduction and development   65 ( 4 )   353 - 359   2019年8月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Freeze-drying of spermatozoa is a convenient and safe method to preserve mammalian genetic material without the use of liquid nitrogen or a deep freezer. However, freeze-dried spermatozoa (FD sperm) are not frequently used because of the low success rate of offspring after intracytoplasmic spermatozoa injection (ICSI). In this study, we determined the optimal concentration and a point of action of trehalose as a protectant for the preservation of FD sperm from different mouse strains at room temperature (RT). Although trehalose demonstrated no potential to protect the FD sperm of ICR mice against the freeze-drying procedure itself, the blastocyst rate was significantly improved when FD sperm was preserved for more than 1 month at RT (56-63% vs. 29% without trehalose). The optimal concentration of trehalose was 0.5 M. Importantly, remarkable results were obtained when spermatozoa of inbred mouse strains (C57BL/6N, C3H/He, and 129/Sv) were used, and many offspring were obtained when FD sperm that was preserved for 3 months at RT (26-28% vs. 6-11% of without trehalose) was used. However, when DNA damage in FD sperm was examined by gamma-H2Ax assays, it was found that trehalose failed to protect the FD sperm from DNA damage. These results suggest that trehalose has the potential to protect other sperm factors rather than sperm DNA during preservation at RT for longer periods and trehalose is more effective for inbred mouse strains.

    DOI: 10.1262/jrd.2019-058

    PubMed

  • Tolerance of the freeze-dried mouse sperm nucleus to temperatures ranging from -196 °C to 150 °C. 査読

    Sayaka Wakayama, Daiyu Ito, Yuko Kamada, Shigenobu Yonemura, Masatoshi Ooga, Satoshi Kishigami, Teruhiko Wakayama

    Scientific reports   9 ( 1 )   5719 - 5719   2019年4月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    It has long been believed that tolerance against extreme environments is possible only for 'lower' groups, such as archaea, bacteria or tardigrades, and not for more 'advanced' species. Here, we demonstrated that the mammalian sperm nucleus also exhibited strong tolerance to cold and hot temperatures. When mouse spermatozoa were freeze-dried (FD), similar to the anhydrobiosis of Tardigrades, all spermatozoa were ostensibly dead after rehydration. However, offspring were obtained from recovered FD sperm nuclei, even after repeated treatment with conditions from liquid nitrogen to room temperature. Conversely, when FD spermatozoa were heated at 95 °C, although the birth rate was decreased with increasing duration of the treatment, offspring were obtained even for FD spermatozoa that had been heat-treated for 2 h. This period was improved up to 6 h when glucose was replaced with trehalose in the freeze-drying medium, and the resistance temperature was extended up to 150 °C for short periods of treatment. Randomly selected offspring grew into healthy adults. Our results suggest that, when considering the sperm nucleus/DNA as the material that is used as a blueprint of life, rather than cell viability, a significant tolerance to extreme temperatures is present even in 'higher' species, such as mammals.

    DOI: 10.1038/s41598-019-42062-8

    PubMed

  • Assessing the tolerance to room temperature and viability of freeze-dried mice spermatozoa over long-term storage at room temperature under vacuum. 査読

    Yuko Kamada, Sayaka Wakayama, Ikue Shibasaki, Daiyu Ito, Satoshi Kamimura, Masatoshi Ooga, Teruhiko Wakayama

    Scientific reports   8 ( 1 )   10602 - 10602   2018年7月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Freeze-drying has been frequently used to preserve food and microorganisms at room temperature (RT) for extended periods of time; however, its application to mammalian species is difficult. Here, we developed a method to prolong the stability of freeze-dried (FD) mice spermatozoa at RT for more than one year without using any cryoprotectant agents. Our data showed that maintaining a vacuum in ampoules is critical to ensuring the viability of FD spermatozoa, as the stability of spermatozoa DNA increased when imperfectly vacuumed ampoules were detected using a non-destructive test and eliminated. Finally a large number of healthy offspring were obtained from mice oocytes fertilized with FD spermatozoa stored at RT for more than one year. Although the birth rate from three-month stored spermatozoa was lower than that from one-day stored spermatozoa, no further reduction was observed even in one-year stored spermatozoa. Therefore, FD spermatozoa preserved in this study were highly tolerant to warm temperatures. This method of storage shows a great potential for the preservation of genetic resources of mammalian species, such as genetically-modified mouse strains, without the use of electric power.

    DOI: 10.1038/s41598-018-28896-8

    PubMed

▼全件表示

書籍等出版物

  • 生殖細胞における凍結乾燥技術

    ( 範囲: 第5章3節)

     詳細を見る

    記述言語:日本語   著書種別:学術書

  • The end of the Ice Age and the start of the Space Age: The Freeze-drying of gametes.

    ( 担当: 共著)

     詳細を見る

    記述言語:英語   著書種別:学術書

講演・口頭発表等

  • 国際宇宙ステーションでマウス胚盤胞を凍結する方法の開発

    本藤 香織、佐藤 吉真、伊藤 大裕、若山 照彦、若山 清香

    第117回日本繁殖生物学会大会  2024年9月 

     詳細を見る

    記述言語:日本語   会議種別:口頭(一般)  

  • 産仔へ発育可能なマウス円形精子細胞を識別するAI の開発

    山地 莞梧、若山 清香、伊藤 大裕、重藤 優太郎、吉川 友也、新保 仁、竹内 彰一、若山 照彦

    第117回日本繁殖生物学会大会  2024年9月 

     詳細を見る

    記述言語:日本語   会議種別:口頭(一般)  

  • 凍結乾燥で生じる体細胞核のDNA 損傷を低減する保護剤の検討

    神宮司 拓真、並木 愛、牛込 夏樹、伊藤 大裕、若山 清香、若山 照彦

    第117回日本繁殖生物学会大会  2024年9月 

     詳細を見る

    記述言語:日本語   会議種別:口頭(一般)  

  • グルタミン酸ナトリウムがマウス凍結乾燥精子の作製時に及ぼす保護効果

    牛込夏樹、伊藤大裕、若山清香、若山照彦

    第117回日本繁殖生物学会大会  2024年9月 

     詳細を見る

    記述言語:日本語   会議種別:口頭(一般)  

  • 水による深宇宙放射線防護は月での遺伝資源の永久保存を可能にする

    古澤 勇、黒川 祐菜、牛込 夏樹、山地 莞梧、佐藤 吉真、井上 怜、武田 盛也、市川 遼、杉山 陽大、藤田 真由美、荒木 良子、伊藤 大裕、小平 聡、若山 照彦、若山 清香

    第117回日本繁殖生物学会大会  2023年9月 

     詳細を見る

    記述言語:日本語   会議種別:口頭(一般)  

受賞

  • 2019 JRD Outstanding Paper Award 重要な業績

    2020年9月   The Society for reproduction and Development   Effect of trehalose on the preservation of freeze-dried mice spermatozoa at room temperature

担当授業科目(学内)

  • 生命研究倫理学

    2024年度

  • 発生工学実験

    2024年度

  • 生命環境基礎ゼミ

    2024年度  科目区分:専門教育(学部)

  • 生命環境基礎ゼミ

    2023年度  科目区分:専門教育(学部)

その他の学部学生指導

  • 2024年度

    クラス担任(期間): 2024年 - 継続中

修士・博士論文審査

  • 2024年度

    主査副査分類:副査

    修士 :1人 

社会貢献活動

  • 山梨大学 特色ある研究PR展示 〜発生工学研究展〜

    役割:編集

    2024年12月 - 2025年6月

所属学協会

  • 日本繁殖生物学会

    2023年 - 現在

  • 日本繁殖生物学会

    2018年8月

委員歴

  • 日本繁殖生物学会   若手奨励策検討委員会  

    2024年4月 - 現在